Not sure what to do... Need advice

Kat
So sorry this might be long... I don't know yet if I am pregnant- certainly hoping! And I just have that "feeling". So to give you a background AF was due 3/31 but I didn't get it so glow moved it to 4/7 again didn't get it, glow now says I should get it 4/14. I've been absolutely exhausted (sleeping 9-10hrs and wanting a nap), moody, sensitive, nipples tingled/hurt for a while and then itched, boobs seem to have gotten bigger/fuller, and nipples seem bigger, nauseous, food doesn't sound good or taste right, CP was very high, soft, and closed with creamy/watery CM, it's not very high, medium, and closed and today CM was milky EWCM. Last test I took a couple days ago was a BFN- but didn't use FMU. 
My problem is... I work in a restaurant and once or twice a day I have to fill the Pepsi cooler (no biggy) but I noticed today that when I was lifting the Pepsi flats I got a sharp cramping really low down- after I felt that I made sure I was lifting with my legs. Each flat is 30lbs, and I have to move (sometimes lifting above my head) about 20 of them at least once a day... I know at least later on in pregnancy you can't lift over 30lbs. My dr had mentioned when I am pregnant there's a chance it will be "elevated risk" because my cervix tore quite a bit when I delivered my daughter. But I haven't told my boss we're trying to conceive, and when I am pregnant (if I'm not already) I wouldn't say anything till 12 weeks... But should I be worried about doing "heavy" lifting right now? And if I should be worried about it, how should I go about telling my boss I can't do it? Sorry this is soooo long!